The invention relates to a device for handling fluids comprising at least one channel in a substrate. Devices of this type are e.g. of the “lab on chip” type and can be used, inter alia, for analyzing very small quantities of liquids or to subject fluids to biological or chemical reactions. Devices of this type may also be simple devices with a single duct, such as e.g. used for a flow sensor.
It is of importance that the processes carried out on the device can be monitored and/or controlled accurately.